Although there have been known various compounds exhibiting inhibitory activity on angiotensin converting enzyme, any compound with such activity having a moiety of .omega.-(4-piperidyl)-.alpha.-amino acid has not been known at all.
The present inventors, after intensive search for the compound which exhibits inhibitory activity on angiotensin converting enzyme and is useful as a therapeutic agent for hypertension and circulatory diseases, such as cardiopathy and cerebral apoplexy, succeeded in producing the piperidine derivatives exhibiting excellent actions, and have completed this invention.